Encapsulating Ultrafine Sb Nanoparticles in Na⁺ Pre-Intercalated 3D Porous Ti₃C₂T_x MXene Nanostructures for Enhanced Potassium Storage Performance

Abstract

Taking into consideration the advantages of the highly theoretical capacity of antimony (Sb) and abundant surface redox reaction sites of Na+ pre-intercalated 3D porous Ti3C2T x (Na–Ti3C2T x ) architectures, we elaborately designed the Sb/Na–Ti3C2T x hybrid with Sb nanoparticles homogeneously distributed in 3D porous Na–Ti3C2T x architectures through a facile electrostatic attraction and carbothermic reduction process. Na–Ti3C2T x architectures with more open structures and larger active specific surface area not only could certainly alleviate volume changes and hinder the aggregation of Sb nanoparticles in the cycling process to improve the structural stability but also significantly strengthen the electron-transfer kinetics and provide unblocked K+ diffusion channels to promote ionic/electronic transport rate. Furthermore, the ultrafine Sb nanoparticles could efficiently shorten K+ transport distance and expose more accessible active sites to improve capacity utilization. DFT calculations further indicate that the Sb/Na–Ti3C2T x anode effectively decreases the adsorption energy of K+ and accelerates the potassiation process. Benefiting from the synergistic effect, it exhibits an outstanding specific capacity of 392.2 mAh g–1 at 0.1 A g–1 after 450 cycles and a stable capacity reservation with a capacity fading rate of 0.03% per cycle at 0.5 A g–1. Our work may encourage further research on advanced MXene-based hybrid materials for high-performance PIBs.

Achieving High‐Performance 3D K+‐Pre‐intercalated Ti3C2Tx MXene for Potassium‐Ion Hybrid Capacitors via Regulating Electrolyte Solvation Structure

“…As shown in Figure 1 g and Figure S5, the presence of the unique signal of K in 3D K + ‐Ti 3 C 2 T x confirms the success of our K + pre‐intercalation strategy. There are two satellite peaks for Ti 2p 1/2 and Ti 2p 3/2 at 459.8 and 454.8 eV, which can be further deconvoluted to the characteristic peaks corresponding to Ti−C bonds, Ti(II) and Ti−O bonds, respectively (Figure S5a,d,g) [21, 29] . More importantly, three major peaks derived from O 1s (Ti‐O, C‐Ti‐O x and C‐Ti‐OH x ) and the strong F 1s spectra reflect the existence of O, OH, and F functional groups on the Ti 3 C 2 T x surface (Figure S5b,e,h) [35] .…”

Recent Advances in the Synthesis and Energy Applications of 2D MXenes

“…They also encapsulated ultrafine Sb nanoparticles in porous Ti 3 C 2 T x through electrostatic attraction resulting in enhanced electrochemistry performance. [99]…”

Strongly Coupled 2D Transition Metal Chalcogenide-MXene-Carbonaceous Nanoribbon Heterostructures with Ultrafast Ion Transport for Boosting Sodium/Potassium Ions Storage

“…The D K values for the potassiation process varied in range of 10 –10 to 10 –11 cm 2 s −1 and were 10 –8 ~ 10 –10 cm 2 s −1 for the depotassation process. The high K + diffusion coefficients confirmed that the ternary Cu 1.75 Se-MXene-CNRib anode allows rapid K + migration and storage at a more efficient kinetic behavior, and it can be a competitive anode for PIBs [ 21 , 36 – 39 ].…”

“…It is very clear that the novel ternary MSe-MXene-CNRib heterostructures are capable of exceptional Na and K ions storages with excellent capacity at both low and high rates [14,22,28,[33][34][35][36][37][38][39]. The exceptional electrochemical performance is mainly attributed to the unique combination of 2D nanomaterials, which provide abundant active storage sites on the surfaces and at the interfaces for the large Na and K ions and allow ultrafast ion transport and migration within the porous structures.…”